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1 7/8” or 2” Headers???

Zig

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We typically recommend 1 7/8 until 9-1000whp.. the 2" are fine at a tad lower levels, but an unnecessary addition. You have to lower the motor/trim the studs for most 2" applications.

If you ever end up wanting to go with headers (I saw the comment on the 3/36k warranty), checkout our Lethal ones. They are 1 7/8" and fit perfectly.

https://www.lethalperformance.com/l...it-2015-2024-mustang-gt-5-0l-1151h412-lp.html
Is this due to backpressure or flow?
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Logan@Lethal

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Is this due to backpressure or flow?
Is what due to backpressure? The swap from 1 7/8 to 2"?
If so, in a sense, yes. You do not want excessive exhaust manifold pressure. This is where you'd create a bottleneck because the pressure is higher than even the boost pressure. This will yield higher temperatures, less efficiency (power left on the table)..
 

Zig

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Is what due to backpressure? The swap from 1 7/8 to 2"?
If so, in a sense, yes. You do not want excessive exhaust manifold pressure. This is where you'd create a bottleneck because the pressure is higher than even the boost pressure. This will yield higher temperatures, less efficiency (power left on the table)..
Was attempting to bring the thread back on topic.

Was in reference to the recommendation of 1 7/8” primaries.

if 1/8” doesn’t make any difference why the size selection, as in why not just slap on the largest that will fit?
 

Logan@Lethal

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Was attempting to bring the thread back on topic.

Was in reference to the recommendation of 1 7/8” primaries.

if 1/8” doesn’t make any difference why the size selection, as in why not just slap on the largest that will fit?
2" require lowering the motor and stud trimming.. and can have some lower end torque loss if inadequate pressure is built (too low of power)
 
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Sf22giants

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I just bought a whipple stage 2 and 1 7/8 long tubes from lethal performance. I also have a Dark Horse. For street cruising and infrequent track use, that is a proven combo, which is why I went with it
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